100 degrees, you sure it's not more like 20-30 degrees?
100 degrees is almost a third of a turn, I hope you haven't been driving it that way.
There is a nut on top of the steering box with a slotted screw in the center. Loosen the nut and turn the screw down. DON'T over tighten it! If the screw drops in the box, look for another steering box.
I have grease in mine and it leaks. One of these days I'll have PS. There have many posts on steering lube do a search.
LG